Effects of Agglomerate Arrangement on the Performance of a PEMFC Cathode Catalyst Layer

Proton exchange membrane fuel cells (PEMFCs) as efficient and advantageous power sources are currently near the stage of full commercialization in the vehicle industry. However, the simulation of their cathode electrode faces with some challenges due to the complicated physics and microstructure. In the present study, the reactive air flow in a cathode electrode of a PEMFC is simulated through a multi-scale lattice Boltzmann approach. In this regard, a two-dimensional single-phase lattice Boltzmann agglomerate model is presented and validated; then it is applied to model cathode electrode consisting of catalyst layer (CL), gas diffusion layer (GDL) and gas flow channel. To investigate the effects of agglomerate arrangement on the CL performance, species distributions in the pore region, electrical potential distribution in the electrolyte film, and current density distribution at the interface of membrane and CL are presented and analyzed for both uniform and non-uniform agglomerate arrangements. The results establish the fact that the distribution of species, water content, electric potential and current density in the CL, i.e. the CL performance, are strongly affected by agglomerate arrangement in the CL. The results of this study can be helpful to improve catalyst layer microstructure, and subsequently its performance. Besides, the presented model can be extended to three dimensions for further investigation of CL microstructure impact.